Abstract 4991: Hodgkin and Reed-Sternberg cells produce soluble mediators to modulate endothelial cell-T cell interactions in classical Hodgkin Lymphoma.
Authors: Chee Wai Fhu, Siew Meng Chong, Yaw Chyn Lim
Journal: Cancer Research (2013)

Abstract Classical Hodgkin Lymphoma (CHL) is characterized by the presence of a small minority of malignant Hodgkin and Reed-Sternberg cells (H-RS cells) surrounded by a massive mixed of inflammatory infiltrates. CD4+ T helper 2 cells, regulatory T cells and CD8+ cytotoxic T cells form a significant part of this infiltrates. The mechanisms underlying T cell recruitment into the involved lymph nodes are still unknown. The aim of this study is to elucidate whether H-RS cells can modulate endothelial cell-T cell interactions in CHL. KM-H2 cell is used as a representative H-RS cell line. Cell based ELISA and FACS are employed to check the adhesion molecules expression on the endothelial cells (EC). Static transwell transmigration and dynamic flow system are used to determine the interaction between EC and T cell. Western blot is used to study the mechanism involved in KM-H2 cell activation. ELISA analyses show KM-H2 culture supernatant (C/S)-stimulated EC up-regulates ICAM-1, VCAM-1 and E-selectin expression. Static transwell transmigration assay shows C/S stimulated EC enhanced naïve and memory T cells transmigration in response to CXCL12. Besides that, C/S stimulated EC demonstrates higher interaction with naïve and memory T cells in dynamic flow condition. In vitro L929 cytotoxic assay shows that KM-H2 cells produce soluble lymphotoxin-α. FACS analyses show that lyphotoxin-α neutralizing antibody treated C/S has less stimulatory effect on ICAM-1, VCAM-1 and E-selectin expression on stimulated EC compared to respective control. SP600125 and Indomethacin treated KM-H2 cells produce less soluble lymphotoxin-α as determined by L929 cytotoxic assay. ELISA analyses shows reduced ICAM-1, VCAM-1 and E-selectin expression on EC stimulated by C/S harvested from JNK (SP600125) and COX (Indomethacin) inhibitors treated KM-H2 cells. Western blot analysis shows that treatment of KM-H2 cells with SP600125 reduced expression of phosphorylated JNK and C-Jun protein. Level of phosphorylated C-Fos and total C-Fos remained unchanged in JNK inhibitor treated KM-H2 cells. However, level of phosphorylated C-Fos and total C-Fos reduced significantly in COX inhibitor treated KM-H2 cells while level of phosphorylated JNK and C-Jun is up-regulated in Indomethacin treated KM-H2 cells. Production of lympotoxin-α by H-RS cells is reconfirmed by immunohistochemistry staining on tissue samples from Hodgkin Lymphoma patients. Our data suggest that in CHL, malignant H-RS cells secrete soluble lymphotoxin-α which can modulate EC function. JNK and COX pathways are involved in regulating the production of lymphotoxin-α from KM-H2 cells. Citation Format: Chee Wai Fhu, Siew Meng Chong, Yaw Chyn Lim. Hodgkin and Reed-Sternberg cells produce soluble mediators to modulate endothelial cell-T cell interactions in classical Hodgkin Lymphoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4991. doi:10.1158/1538-7445.AM2013-4991